Union of New Brunswick Indians

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Contaminants in Breast Milk

There is agreement that all our bodies carry heavy contaminant loads from man-made chemicals.

There is agreement that breastfeeding is indispensable for human growth and development.

There is not agreement on the health effects of contaminants in breastmilk on infants & children.

Breastfed infants are considered to be at the very top of the food chain for the simple reason that their source of nourishment is other humans, who are already at the top of the food chain.

Persistent organic pollutants (POPs) all tend to become magnified in the food chain over time.

Breastfeeding infants are thus the final target of POPs.

10 to 20 times as much of a mother's body burden of developmental toxins such as dioxins and PBDEs is transferred to the infant via the milk as by the transplacental route.

Highs, mid-levels and lows of infant exposures to certain toxins seem to correlate closely with highs, mid-levels and lows of autism or ASD traits, Publication of Pollution Action. 
Initiation of breastfeeding brings a sudden, major increase in toxins ingested, compatible with abrupt later appearance of negative effects. Decline of eye contact, beginning two months after birth, was found in infants who were later diagnosed with ASD.  This was not merely failure to develop, it was considered to be a derailment of initially satisfactory development.14a  The study’s authors saw this to be especially significant since “deficits in eye contact have been a hallmark of autism since the condition’s initial description.

Through mechanisms, known and unknown, breastfeeding has a positive impact on child health, since breastmilk strengthens the immune system. However, heavy loads of environmental contaminants may threaten the capacity to reproduce immune-strengthening breastmilk.

The Postnatal Period

Why is the Early-Postnatal Period a Time of Special Concern regarding Effects of Developmental Toxins?

  • A time of high vulnerability of the developing brain to effects of known, relatively widespread toxins
  • A time of greatly increased exposures to neuro-developmental toxins
  • The brain’s period of greatest cell proliferation is during the first two years of life
  • Various brain regions are especially vulnerable to toxins during their peak developmental periods
  • The cerebellum, which coordinates muscle (and eye) movement, is growing especially rapidly in the year after birth and is therefore quite vulnerable to toxins in this period.  Neurons in the cerebellum develop following birth, whereas neurons in the cortex develop mostly before birth

Cerebellar injury seems to be the most consistent neuropathology finding among children with ASD

Contaminants in Human Milk: Weighing the Risks against the Benefits of Breastfeeding
M. Nathaniel Mead. Environ Health Perspect. 2008 Oct; 116(10): A426–A434.
Given the tendency for persistent organic pollutants (POPs), pesticides, heavy metals, and other contaminants to accumulate in human milk, researchers and parents alike are asking whether the nursling’s exposure to these pollutants might reduce or even override the health benefits.

Environmental Contaminants in Breast Milk.
Krista Nickerson, Vol. 51, Iss. 1, Jan.–Feb.2006, Pgs 26–34
Toxic environmental contaminants can be transferred from mother to infant via breastfeeding. Persistent organic pollutants (POPs) are a family of lipophilic stable chemicals that bio-accumulate in adipose tissue and create a lasting toxic body burden. Breastfeeding provides a significant source of exposure to POPs early in human life, the effects of which are unknown, and is the subject of a growing body of research. Despite the possibility of harm from environmental contaminants in breast milk, breastfeeding is still recommended as the best infant feeding method. This article reviews what is known about POPs in breast milk and their effect on infant development to inform clinicians about the issue, provide recommendations for practice, and promote environmental and public health policies that reduce human exposure to harmful pollutants.

Developmental Environmental Toxins

There appears to be an extremely high correlation between hazardous infant exposures to toxins and the lactation process, which mobilizes toxins that have been stored in a mother’s body fat and excretes them to the infant in highly-concentrated form.

Exposures to neuro-developmental toxins are often extraordinarily high in the early-postnatal period, by comparison with established national or international standards and also in relation to prenatal exposures.
Publication of Pollution Action

Children’s Environmental Health Project

The Children’s Environmental Health Project was designed by the Canadian Association of Physicians for the Environment (CAPE). It is intended to introduce clinicians (and their patients) to the fundamentals and broad context of children’s environmental health issues.  The project also covers environmental history-taking and provides links to additional resources that may be useful to the interested individual. Lastly, a commentary is provided on the physician’s role in primary prevention of environmental health problems in children.

The Canadian Association of Physicians for the Environment (CAPE), along with its sister organization the Canadian Health and Environment Education and Research Foundation (CHEER), are the only organizations in Canada dedicated to speaking for physicians on environmental issues. CAPE does evidence-based advocacy work related to these issues, while CHEER conducts research, educates the public, and analyses policies related to environmental issues, with particular attention to their effects on human health.

The primary tenet of the Hippocratic Oath is to do no harm. The medical profession therefore fundamentally endorses a precautionary approach that strives to protect the child when there is profound uncertainty and incomplete understanding of the risks from environmental toxins.

Health Canada

Maternal-Infant Research on Environmental Chemicals (The MIREC Study). 
Studies and reports have raised concerns about the number of chemicals in our bodies and the health effects that may be associated with the levels measured. Canadian data on this issue are limited.

This Canadian study has the following purposes:

  • to measure the extent to which pregnant women and their babies are exposed to common environmental chemicals;
  • to measure some of the beneficial elements in human breast milk;
  • to assess what health risks, if any, are associated with the chemical levels measured, with a focus on heavy metals such as lead and mercury;
  • to create a data and biological specimen bank for further research on fetal growth, pregnancy and health of mother and baby.

Maternal and fetal exposure to lead, mercury, cadmium and manganese: the MIREC Study. Arbuckle TE, Liang CL, Morisset AS, Fisher M, Weiler H, Mihai Cirtiu C, Legrand M, Davis K, Ettinger AS, Fraser WD, the MIREC Study Group. Chemosphere. 2016 Nov;163:270-82. doi: 10.1016/j.chemosphere.2016.08.023. Epub 2016 Aug 16.
Given the susceptibility of the fetus to toxicants, it is important to estimate their exposure. Cd, Pb, Mn and total Hg were measured in maternal blood from the 1st and 3rd trimesters, umbilical cord blood, and infant meconium. Nutrient intakes of vitamin D, iron, and calcium (Ca) were assessed using a food frequency questionnaire and a dietary supplement questionnaire.  While Cd was rarely detected in cord blood (19%) or meconium (3%), median Pb (0.77 ìg/dL), Mn (31.87 ìg/L) and Hg (0.80 ìg/L) concentrations in cord blood were significantly higher than in maternal blood. Significant negative associations were observed between estimated Ca intake and maternal Cd, Pb, Mn and Hg, as well as cord blood Pb. Vitamin D intake was associated with lower maternal Cd, Pb, and Mn as well as Pb in cord blood.  Even at current metal exposure levels, increasing dietary Ca and vitamin D intake during pregnancy may be associated with lower maternal blood Pb and Cd concentrations and lower Pb in cord blood.

Maternal blood metal levels and fetal markers of metabolic function. Ashley-Martin J, Dodds L, Arbuckle TE, Ettinger AS, Shapiro GD, Fisher M, Taback S, Bouchard MF, Monnier P, Dallaire R, Fraser WD. Environmental Research. 2015;136:27-34.
This study supports the proposition that maternal levels of cadmium influence cord blood adipokine levels in a sex-dependent manner. Further investigation is required to confirm these findings and to determine how such findings at birth will translate into childhood anthropometric measures.

Air pollution exposure during pregnancy and fetal markers of metabolic function: the MIREC Study. Lavigne E, Ashley-Martin J, Dodds L, Arbuckle TE, Hystad P, Johnson M, Crouse DL, Ettinger AS, Shapiro GD, Fisher M, Morisset AS, Taback S, Bouchard MF, Sun L, Monnier P, Dallaire R, Fraser WD. American Journal of Epidemiology. 2016 2016 May 1;183(9):842-51. doi: 10.1093/aje/kwv256. Epub 2016 Mar 29.
Significant associations were seen between air pollution markers and cord blood leptin levels in models that adjusted for birth weight z score but not in models that did not adjust for birth weight z score. The roles of prenatal exposure to air pollution and fetal metabolic function in the potential development of childhood obesity should be further explored.

Concentrations of persistent organic pollutants in maternal and cord bloodfrom the maternal-infant research on environmental chemicals (MIREC) cohort study. Fisher M, Arbuckle TE, Liang CL, LeBlanc A, Gaudreau E, Foster WG, Haines D, Davis K, Fraser WD. Environmental Health. 2016 May 4;15(1):59.
Pregnant women are an especially important population to monitor for environmental exposures given the vulnerability of the developing fetus. During pregnancy and lactation chemical body burdens may change due to the significant physiological changes that occur. Developmental exposures to some persistent organic pollutants (POPs) have been linked with adverse health outcomes. Similar to other studies, we found parity, maternal age, income, education, smoking status, pre-pregnancy BMI and fish consumption to be significant predictors for most chemicals. Those participants who were foreign-born had significantly higher concentrations of organochlorinated pesticides and PCBs.

Other Publications

A Strategy for Comparing the Contributions of Environmental Chemicals and Other Risk Factors to Neurodevelopment of Children. Bellinger DC. 2012.  Environ Health Perspect 120:501–507